Compounds for the treatment of peripheral neuropathies

ABSTRACT

A compound of formula A1 or A2 for use in the treatment of a demyelinating peripheral neuropathy: 
     
       
         
         
             
             
         
       
         
         
           
             wherein 
             A is COOR 5 , OPO(OR 5 ) 2 , PO(OR 5 ) 2 , SO 2 OR 5 , POR 5 OR 5  or 1H-tetrazol-5-yl, R 5  being H or an ester-forming group, optionally C 1-6 alkyl; 
             W is a bond, C 1-3 alkylene or C 2-3 alkenylene; 
             Y is C 6-10 aryl or C 2-9 heteroaryl eg C 3-9 heteroaryl, optionally substituted by 1 to 3 radicals selected from halogen, OH, NO 2 , C 1-6 alkyl, C 1-6 alkoxy; halo-substituted C 1-6 alkyl and halo-substituted C 1-6 alkoxy; 
             Z is chosen from: 
           
         
       
    
     
       
         
         
             
             
         
       
         
         
           
             wherein the asterisks of Z indicate the point of attachment between —C(R 3 )(R 4 )— and A of Formula Ia or Ib, respectively; R 6  is chosen from hydrogen and C 1-6 alkyl; and J 1  and J 2  are independently methylene or a heteroatom chosen from S, O and NR 5 ; wherein R 5  is chosen from hydrogen and C 1-6 alkyl; and any alkylene of Z can be further substituted by one to three radicals chosen from halo, hydroxy, C 1-6 alkyl; or R 6  can be attached to a carbon atom of Y to form a 5-7 member ring; 
             R 1  is C 6-10 aryl or C 2-9 heteroaryl eg C 3-9 heteroaryl, optionally substituted by C 1-6 alkyl, C 6-10 aryl, C 6-10 arylC 1-4 alkyl, C 3-9 heteroaryl, C 3-9 heteroarylC 1-4 alkyl, C 3-8 cycloalkyl, C 3-8 cycloalkylC 1-4 alkyl, C 3-8 heterocycloalkyl or C 3-8 heterocycloalkylC 1-4 alkyl; wherein any aryl, heteroaryl, cycloalkyl or heterocycloalkyl of R 1  may be substituted by 1 to 5 groups selected from halogen, C 1-6 alkyl, C 1-6 alkoxy and halo substituted-C 1-6 alkyl or —C 1-6 alkoxy; 
             R 2  is H, C 1-6 alkyl, halo substituted C 1-6 alkyl, C 2-6 alkenyl or C 2-6 alkynyl; and 
             each of R 3  and R 4 , independently, is H, halogen, OH, C 1-6 alkyl, C 1-6 alkoxy or halo substituted C 1-6 alkyl or C 1-6 alkoxy; 
             and the N-oxide derivatives thereof or prodrugs thereof, 
             or a pharmacologically acceptable salt, solvate or hydrate thereof.

FIELD OF THE INVENTION

The present invention relates to immunosuppressant compounds and theiruse in therapy.

BACKGROUND TO THE INVENTION

The inflammatory or immune-mediated neuropathies are a diverse group ofdiseases which include such peripheral neuropathies as Guillain-Barrésyndrome (GBS), chronic inflammatory demyelinatingpolyradiculoneuropathy (CIDP), multifocal motor neuropathy withconduction block (MMN), and paraproteinaemic demyelinating peripheralneuropathy (PDN). The pathogenesis of the inflammatory neuropathies isstill under investigation.

A number of demyelinating peripheral neuropathies are next discussed.

Peripheral neuropathies, therefore, include Guillain-Barré syndrome,which is an acute, autoimmune, polyneuropathy affecting the peripheralnervous system, usually triggered by an acute infectious process. Thereare several types of GBS, the most common form being acute inflammatorydemyelinating polyneuropathy (AIDP). GBS is frequently severe andusually exhibits as an ascending paralysis noted by weakness in the legsthat spreads to the upper limbs and the face along with complete loss ofdeep tendon reflexes. The suppressor T cell response is reducedsuggesting a cell-mediated immunological reaction directed at theperipheral nerves.

Multifocal motor neuropathy is a progressive muscle disordercharacterized by muscle weakness in the hands, with differences from oneside of the body to the other in the specific muscles involved. Symptomsalso include muscle wasting, cramping, and involuntary contractions ortwitching of the leg muscles. Multifocal motor neuropathy is recognizedto be an immune-mediated disorder.

Paraproteinaemic Demyelinating Neuropathy is a major cause of late onsetdemyelinating neuropathy, very similar to CIDP though more chronic. Itmostly affects people of 60 years and over. Patients have many symptomsto contend with and it tends to be a long-term illness

Chronic inflammatory demyelinating polyneuropathy (CIDP) ischaracterised by progressive weakness and impaired sensory function inthe legs and arms. These symptoms are caused by damage to the myelinsheath of the peripheral nerves. It often presents with symptoms thatinclude tingling or numbness (beginning in the toes and fingers),weakness of the arms and legs, loss of deep tendon reflexes, fatigue,and abnormal sensations. The prevalence of CIDP is about 2 to 4 per100,000. The pathogenesis is uncertain but may involve both T and Bcell-mediated mechanisms.

The course of CIDP varies widely among individuals. Some may have a boutof CIDP followed by spontaneous recovery, while others may have manybouts with partial recovery in between relapses. CIDP leads to severedisability in a considerable number of patients. Current treatments areaimed at modulating the immune response to achieve remission andmaintain functional status.

WO 2004/103306 and US 2005/0014728 describe compounds useful in thetreatment of diseases or disorders mediated by lymphocyte interactions.The aforesaid publications are incorporated herein by reference in theirentirety for all purposes, in particular the following parts of US2005/0014728: paragraphs [0006] to [0015], [0022] to [0042], [0102] to[0124] and [0126] to [0149] and Table 1. Particularly to be mentionedare Examples 1 to 5 of US 2005/0014728.

SUMMARY OF THE INVENTION

In one aspect of the invention there are provided compounds as mentionedbelow for use in the treatment of a peripheral neuropathy, e.g. CIDP.Another aspect of the invention resides in a method of treating asubject having a peripheral neuropathy, e.g. CIDP, comprisingadministering to the subject an effective amount of a compound asmentioned below. A further aspect of the invention is the use of acompound as mentioned below for the manufacture of a medicament for usein treating a peripheral neuropathy, e.g. CIDP.

The compounds to which the application relates are compounds asdisclosed in WO 04/103306 and US 2005/0014728, WO 05/000833, WO05/103309 or WO 05/113330, e.g. compounds of formula A1 or A2

wherein

A is COOR₅, OPO(OR₅)₂, PO(OR₅)₂, SO₂OR₅, POR₅OR₅ or 1H-tetrazol-5-yl, R₅being H or an ester-forming group, e.g. C₁₋₆alkyl;

W is a bond, C₁₋₃alkylene or C₂₋₃alkenylene;

Y is C₆₋₁₀aryl or C₂₋₉heteroaryl eg C₃₋₉heteroaryl, optionallysubstituted by 1 to 3 radicals selected from halogen, OH, NO₂,C₁₋₆alkyl, C₁₋₆alkoxy; halo-substituted C₁₋₆alkyl and halo-substitutedC₁₋₆alkoxy;

Z is chosen from:

wherein the left and right asterisks of Z indicate the point ofattachment between —C(R₃)(R₄)— and A of Formula Ia or Ib, respectively;R₆ is chosen from hydrogen and C₁₋₆alkyl; and J₁ and J₂ areindependently methylene or a heteroatom chosen from S, O and NR₅;wherein R₅ is chosen from hydrogen and C₁₋₆alkyl; and any alkylene of Zcan be further substituted by one to three radicals chosen from halo,hydroxy, C₁₋₆alkyl; or R₆ can be attached to a carbon atom of Y to forma 5-7 member ring;

R₁ is C₆₋₁₀aryl or C₂₋₉heteroaryl eg C₃₋₉heteroaryl, optionallysubstituted by C₁₋₆alkyl, C₆₋₁₀aryl, C₆₋₁₀arylC₁₋₄alkyl, C₃₋₉heteroaryl,C₃₋₉heteroarylC₁₋₄alkyl, C₃₋₈cycloalkyl, C₃₋₈cycloalkylC₁₋₄alkyl,C₃₋₈heterocycloalkyl or C₃₋₈heterocycloalkylC₁₋₄alkyl; wherein any aryl,heteroaryl, cycloalkyl or heterocycloalkyl of R₁ may be substituted by 1to 5 groups selected from halogen, C₁₋₆alkyl, C₁₋₆alkoxy and halosubstituted-C₁₋₆alkyl or —C₁₋₆alkoxy;

R₂ is H, C₁₋₆alkyl, halo substituted C₁₋₆alkyl, C₂₋₆alkenyl orC₂₋₆alkynyl; and

each of R₃ or R₄, independently, is H, halogen, OH, C₁₋₆alkyl,C₁₋₆alkoxy or halo substituted C₁₋₆alkyl or C₁₋₆alkoxy;

and the N-oxide derivatives thereof or prodrugs thereof,

or a pharmacologically acceptable salt, solvate or hydrate thereof.

Also provided are pharmaceutical formulations for use in treating aperipheral neuropathy, e.g. CIDP and comprising a compound of thedisclosure and, optionally, a pharmaceutically acceptable diluent orcarrier. In embodiments, the pharmaceutical formulations contain one ormore additional therapeutic agents.

The invention also provides a product comprising a compound of thedisclosure and a therapeutic agent as a combined preparation forsimultaneous, separate or sequential use in treating a peripheralneuropathy, e.g. CIDP.

In another aspect, the invention provides a pharmaceutical formulationcomprising a compound of the disclosure and a therapeutic agent, thetherapeutic agent being useful for the treatment of a peripheralneuropathy, e.g. CIDP.

The compounds of the invention can exist in different forms, such asfree acids, free bases, esters and other prodrugs, salts and tautomers,for example, and the disclosure includes all variant forms of thecompounds.

The extent of protection includes counterfeit or fraudulent productswhich contain or purport to contain a compound of the inventionirrespective of whether they do in fact contain such a compound andirrespective of whether any such compound is contained in atherapeutically effective amount.

Included in the scope of protection are packages which include adescription or instructions which indicate that the package contains aspecies or pharmaceutical formulation of the invention and a productwhich is or comprises, or purports to be or comprise, such a formulationor species. Such packages may be, but are not necessarily, counterfeitor fraudulent.

Features, integers, characteristics, compounds, chemical moieties orgroups described in conjunction with a particular aspect, embodiment orexample of the invention are to be understood to be applicable to anyother aspect, embodiment or example described herein unless incompatibletherewith.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A shows the variation of neurological score with no. of days fromimmunisation for EAN rats treated with water vehicle and CMC vehicle.

FIG. 1B shows the variation of neurological score with no. of days fromimmunisation for EAN rats treated with 3 and 10 mg/kg concentrationcompound A suspensions.

FIG. 2A shows the variation in body weight with no. of days fromimmunisation for EAN rats treated with water vehicle and CMC vehicle.

FIG. 2B shows the variation in body weight with no. of days fromimmunisation for EAN rats treated with 3 and 10 mg/kg concentrationcompound A suspensions.

DESCRIPTION OF VARIOUS EMBODIMENTS

Definitions

In this specification, unless otherwise defined:

Alkyl, alkenyl, alkynyl

“Alkyl” as a group and as a structural element of other groups, forexample halo-substituted-alkyl, alkoxy, acyl, alkylthio, alkylsulfonyland alkylsulfinyl, can be either straight-chained or branched, andunless otherwise indicated may have from 1 to 6 carbon atoms. A C₁-C₆alkyl moiety may have 1, 2, 3, 4, 5 or 6 carbon atoms. “Alkenyl” as agroup and as a structural element of other groups contains one or morecarbon-carbon double bonds, and can be either straight-chain, orbranched. Double bonds can be in the cis- or trans-configuration.“Alkynyl” as a group and as structural element of other groups andcompounds contains at least one C≡C triple bond and can also contain oneor more C═C double bonds, and can, so far as possible, be eitherstraight-chain or branched. Unless otherwise indicated, alkenyl andalkynyl residues may have 2, 3, 4, 5 or 6 carbon atoms. Any cycloalkylgroup, alone or as a structural element of other groups, can contain 3,4, 5, 6, 7 or 8 carbon atoms, preferably 3, 4, 5 or 6 carbon atoms.“Alkylene” and “alkenylene” are divalent radicals derived from “alkyl”and “alkenyl” groups, respectively. In this application, any alkyl groupof R₁ is optionally an interrupted alkyl group which has a methylenereplaced by a member of the group selected from —S—, —S(O)—, —S(O)₂—,—NR²⁰— and —O— (wherein R²⁰ is hydrogen or C₁₋₆alkyl). These groupsinclude, for example, —CH₂—O—CH₂—, —CH₂—S(O)₂—CH₂—, —(CH₂)₂—NR²⁰—CH₂,—CH₂—O—(CH₂)₂—. In one embodiment, there are no such interrupted alkylgroups; included thereof is a class of compounds in which all alkylgroups are uninterrupted.

Aryl

“Aryl” means a monocyclic or fused bicyclic aromatic ring assemblycontaining six to ten ring carbon atoms. For example, C₆-₁₀aryl can bephenyl, biphenyl or naphthyl, preferably phenyl. A fused bicyclic ringcan be partially saturated, for example, 1,2,3,4-tetrahydro-naphthalene,and the like. “Arylene” means a divalent radical derived from an arylgroup.

For example, arylene as used in this application can be phenylene,biphenylene, naphthylene and the like.

Halogen

“Halo” or “halogen” means F, Cl, Br or I, preferably F or Cl.Halo-substituted alkyl groups and compounds can be partially halogenatedor perhalogenated, whereby in the case of multiple halogenation, thehalogen substituents can be identical or different. A preferredperhalogenated alkyl group is for example trifluoromethyl ortrifluoromethoxy.

Heteroaryl

“Heteroaryl” means aryl, as defined in this application, with theinclusion in the ring structure of at least one heteroatom moietyselected from N, O or S, and each ring is comprised of 5 to 6 ringatoms, unless otherwise stated. For example, C₂heteroaryl includesoxadiazole, triazole, and the like. C₉heteroaryl includes quinoline,1,2,3,4-tetrahydro-quinoline, and the like. C₂₋₉heteroaryl as used inthis application includes thienyl, pyridinyl, furanyl, isoxazolyl,benzoxazolyl or benzo[1,3]dioxolyl, preferably thienyl, furanyl orpyridinyl. “Heteroarylene” means heteroaryl, as defined in thisapplication, provided that the ring assembly comprises a divalentradical. A fused bicyclic heteroaryl ring system can be partiallysaturated, for example, 2,3-dihydro-1H-isoindole,1,2,3,4-tetrahydro-quinoline, and the like.

Substituted

Unless otherwise indicated, the term “substituted” as used herein inreference to a moiety means that one or more, especially up to 5, moreespecially 1, 2 or 3, of the hydrogen atoms in said moiety are replacedindependently of each other by the corresponding number of the describedsubstituents. The term “optionally substituted” as used herein meanssubstituted or unsubstituted.

It will, of course, be understood that substituents are only atpositions where they are chemically possible, the person skilled in theart being able to decide (either experimentally or theoretically)without inappropriate effort whether a particular substitution ispossible. For example, amino or hydroxy groups with free hydrogen may beunstable if bound to carbon atoms with unsaturated (e.g. olefinic)bonds.

Pharmaceutically Acceptable

The term “pharmaceutically acceptable” as used herein includes referenceto those compounds, materials, compositions, and/or dosage forms whichare, within the scope of sound medical judgment, suitable for use incontact with the tissues of human beings or animals without excessivetoxicity, irritation, allergic response, or other problem orcomplication, commensurate with a reasonable benefit/risk ratio. Thisterm includes acceptability for both human and veterinary purposes.

Independently

Where two or more moieties are described as being “each independently”selected from a list of atoms or groups, this means that the moietiesmay be the same or different. The identity of each moiety is thereforeindependent of the identities of the one or more other moieties.

Compounds

The application relates to compounds as disclosed in WO 2004/103306 andUS 2005/0014728, WO 05/000833, WO 05/103309 or WO 05/113330, e.g.compounds of formula A1 or A2

wherein

A is COOR₅, OPO(OR₅)₂, PO(OR₅)₂, SO₂OR₅, POR₅OR₅ or 1H-tetrazol-5-yl, R₅being H or an ester-forming group, e.g. C₁₋₆alkyl;

W is a bond, C₁₋₃alkylene or C₂₋₃alkenylene;

Y is C₆₋₁₀aryl or C₂₋₉heteroaryl eg C₃₋₉heteroaryl, optionallysubstituted by 1 to 3 radicals selected from halogen, OH, NO₂,C₁₋₆alkyl, C₁₋₆alkoxy; halo-substituted C₁₋₆alkyl and halo-substitutedC₁₋₆alkoxy;

Z is chosen from:

wherein the asterisks of Z indicate the point of attachment between—C(R₃)(R₄)— and A of Formula Ia or Ib, respectively; R₆ is chosen fromhydrogen and C₁₋₆alkyl; and J₁ and J₂ are independently methylene or aheteroatom chosen from S, O and NR₅; wherein R₅ is chosen from hydrogenand C₁₋₆alkyl; and any alkylene of Z can be further substituted by oneto three radicals chosen from halo, hydroxy, C₁₋₆alkyl; or R₆ can beattached to a carbon atom of Y to form a 5-7 member ring;

R₁ is C₆₋₁₀aryl or C₂₋₉heteroaryl eg C₃₋₉heteroaryl, optionallysubstituted by C₁₋₆alkyl, C₆₋₁₀aryl, C₆₋₁₀arylC₁₋₄alkyl, C₃₋₉heteroaryl,C₃₋₉heteroarylC₁₋₄alkyl, C₃₋₈cycloalkyl, C₃₋₈cycloalkylC₁₋₄alkyl,C₃₋₈heterocycloalkyl or C₃₋₈heterocycloalkylC₁₋₄alkyl; wherein any aryl,heteroaryl, cycloalkyl or heterocycloalkyl of R₁ may be substituted by 1to 5 groups selected from halogen, C₁₋₆alkyl, C₁₋₆alkoxy and halosubstituted-C₁₋₆alkyl or -C₁₋₆alkoxy;

R₂ is H, C₁₋₆alkyl, halo substituted C₁₋₆alkyl, C₂₋₆alkenyl orC₂₋₆alkynyl; and

each of R₃ or R₄, independently, is H, halogen, OH, C₁₋₆alkyl,C₁₋₆alkoxy or halo substituted C₁₋₆alkyl or C₁₋₆alkoxy;

and the N-oxide derivatives thereof or prodrugs thereof, or apharmacologically acceptable salt, solvate or hydrate thereof.

Further embodiments of the invention are described below. It will beappreciated that the features specified in each embodiment may becombined with other specified features, to provide further embodiments.

A is COOR₅, OPO(OR₅)₂, PO(OR₅)₂, SO₂OR₅, POR₅OR₅ or 1H-tetrazol-5-yl, R₅being H or an ester-forming group, e.g. C₁₋₆alkyl. A is in particularCOOR₅, e.g. COOH.

W is a bond, C₁, C₂ or C₃alkylene or C₂₋₃alkenylene. In embodiments, Wis ethylene.

Y is C₆₋₁₀aryl or C₂₋₉heteroaryl eg C₃₋₉heteroaryl, optionallysubstituted by 1 to 3 radicals selected from halogen, OH, NO₂, alkyl,alkoxy; halo-substituted alkyl and halo-substituted alkoxy, whereinalkyl as a group or as part of alkoxy, whether or not halo-substituted,has 1, 2, 3, 4, 5 or 6 carbon atoms. Y is in particular phenyl orC₆heteroaryl, in either case optionally substituted as aforesaid. Saidaryl, e.g. phenyl, or heteroaryl group may have one substituent, forexample a single said alkyl substituent. An exemplary alkyl substituentis ethyl. Halogen is in particular F or Cl.

Z is a moiety as mentioned above, particularly a heterocyclic group asindicated in WO 2004/103306, e.g. azetidine, particularly azetidinejoined to the remainder of the molecule at the 1- and 3- positions. Alsoto be mentioned are: pyrrolidine and piperidine, in either case joinedto the remainder of the molecule at the 1- and 3- positions; andpiperidine 1,4-disubstituted by the respective moieties forming theremainder of the molecule. These heterocycles are in some compoundsN-substituted (1-substituted) by moiety A and substituted at the 3- or,as the case may be, 4-position by CR₃R₄.

R₁ is C₆₋₁₀aryl or C₂₋₉heteroaryl eg C₃₋₉heteroaryl, optionallysubstituted by C₁₋₆alkyl, C₆₋₁₀aryl, C₆₋₁₀arylC₁₋₄alkyl, C₃₋₉heteroaryl,C₃₋₉heteroarylC₁₋₄alkyl, C₃₋₈cycloalkyl, C₃₋₈cycloalkylC₁₋₄alkyl,C₃₋₈heterocycloalkyl or C₃₋₈heterocycloalkylC₁₋₄alkyl; wherein any aryl,heteroaryl, cycloalkyl or heterocycloalkyl of R₁ may be substituted by 1to 5 groups selected from halogen, C₁₋₆alkyl, C₁₋₆alkoxy and halosubstituted-C₁₋₆alkyl or —C₁₋₆alkoxy. R₁ is in particular phenyl orC₆heteroaryl optionally substituted as aforesaid. R₁ in some embodimentshas two substituents selected from optionally halo-substituted alkylhaving 1, 2, 3, 4, 5 or 6 carbon atoms (e.g. trifluoromethyl),optionally halo-substituted phenyl and optionally halo-substitutedC₃₋₈cycloalkyl (e.g. cyclohexyl), for example R₁ may have one optionallyhalo-substituted alkyl group and one optionally halo-substituted cyclicmoiety selected from phenyl and C₃₋₈ (e.g. C₆)cycloalkyl groups. R₁ isin some compounds phenyl or C₆heteroaryl, particularly phenyl,3,4-disubstituted as aforesaid, as in the case of3-trifluoromethyl-4-cyclohexylphenyl.

R₂ is H, C₁₋₆alkyl, halo substituted C₁₋₆alkyl, C₂₋₆alkenyl orC₂₋₆alkynyl. Alkyl, whether or not halo-substituted, may therefore have1, 2, 3, 4, 5 or 6 carbon atoms. R₂ is in particular methyl.

Each of R₃ and R₄, independently, is H, halogen, OH, C₁₋₆alkyl,C₁₋₆alkoxy or halo substituted C₁₋₆alkyl or C₁₋₆alkoxy. Alkyl, whetheror not halo-substituted and/or part opf alkoxy, may therefore have 1, 2,3, 4, 5 or 6 carbon atoms. R₃ and R₄ may by way of example eachindependently be H, halogen, methyl or halo-substituted methyl. Inparticular, R₃ and R₄ may both be H.

A preferred compound useful for the purposes of the invention is1-{4-[1-(4-Cyclohexyl-3-trifluoromethyl-benzyloxyimino)-ethyl]-2-ethyl-benzyl}-azetidine-3-carboxylicacid:

Further compounds useful for the purposes of the invention include:

Also to be mentioned are other compounds of the Examples and Table 1 ofWO 2004/103306.

Compounds of the invention may be in the form of pharmaceuticallyacceptable salts. The pharmaceutically acceptable salts of the presentdisclosure can be synthesized from the parent compound which contains abasic or acidic moiety by conventional chemical methods. Generally, suchsalts can be prepared by reacting the free acid or base forms of thesecompounds with a stoichiometric amount of the appropriate base or acidin water or in an organic solvent, or in a mixture of the two;generally, nonaqueous media like ether, ethyl acetate, ethanol,isopropanol, or acetonitrile are preferred. Lists of suitable salts arefound in Remington's Pharmaceutical Sciences, 17th ed., Mack PublishingCompany, Easton, Pa., US, 1985, p. 1418, the disclosure of which ishereby incorporated by reference; see also Stahl et al, Eds, “Handbookof Pharmaceutical Salts Properties Selection and Use”, Verlag HelveticaChimica Acta and Wiley-VCH, 2002.

The disclosure thus includes pharmaceutically-acceptable salts of thedisclosed compounds wherein the parent compound is modified by makingacid or base salts thereof. For example the conventional non-toxic saltsor the quaternary ammonium salts which are formed, e.g. from inorganicor organic acids or bases. Examples of such acid addition salts includeacetate, adipate, alginate, aspartate, benzoate, benzenesulfonate,bisulfate, butyrate, citrate, camphorate, camphorsulfonate,cyclopentanepropionate, digluconate, dodecylsulfate, ethanesulfonate,fumarate, glucoheptanoate, glycerophosphate, hemisulfate, heptanoate,hexanoate, hydrochloride, hydrobromide, hydroiodide,2-hydroxyethanesulfonate, lactate, maleate, methanesulfonate,2-naphthalenesulfonate, nicotinate, oxalate, pamoate, pectinate,persulfate, 3-phenylpropionate, picrate, pivalate, propionate,succinate, tartrate, thiocyanate, tosylate, and undecanoate. Base saltsinclude ammonium salts, alkali metal salts such as sodium and potassiumsalts, alkaline earth metal salts such as calcium and magnesium salts,salts with organic bases such as dicyclohexylamine salts,N-methyl-D-glucamine, and salts with amino acids such as arginine,lysine, and so forth. Also, the basic nitrogen-containing groups may bequaternized with such agents as lower alkyl halides, such as methyl,ethyl, propyl, and butyl chloride, bromides and iodides; dialkylsulfates like dimethyl, diethyl, dibutyl; and diamyl sulfates, longchain halides such as decyl, lauryl, myristyl and stearyl chlorides,bromides and iodides, aralkyl halides like benzyl and phenethyl bromidesand others.

The invention includes prodrugs for the active pharmaceutical species ofthe invention, for example in which one or more functional groups areprotected or derivatised but can be converted in vivo to the functionalgroup, as in the case of esters of carboxylic acids convertible in vivoto the free acid, or in the case of protected amines, to the free aminogroup. The term “prodrug,” as used herein, represents in particularcompounds which are rapidly transformed in vivo to the parent compound,for example, by hydrolysis in blood. A thorough discussion is providedin T. Higuchi and V. Stella, Pro-drugs as Novel Delivery Systems, Vol.14 of the A.C.S. Symposium Series, Edward B. Roche, ed., BioreversibleCarriers in Drug Design, American Pharmaceutical Association andPergamon Press, 1987; H Bundgaard, ed, Design of Prodrugs, Elsevier,1985; and Judkins, et al. Synthetic Communications, 26(23), 4351-4367(1996), each of which is incorporated herein by reference.

Prodrugs therefore include drugs having a functional group which hasbeen transformed into a reversible derivative thereof. Typically, suchprodrugs are transformed to the active drug by hydrolysis. As examplesmay be mentioned the following:

Functional Group Reversible derivative Carboxylic acid Esters, includinge.g. alkyl and acyloxyalkyl esters; amides Alcohol Esters, includinge.g. sulfates and phosphates as well as carboxylic acid (e.g. alkanoicacid) esters Amine Amides, carbamates, imines, enamines, Carbonyl(aldehyde, Imines, oximes, acetals/ketals, enol esters, ketone)oxazolidines and thiazoxolidines

Prodrugs also include compounds convertible to the active drug by anoxidative or reductive reaction. As examples may be mentioned:

Oxidative Activation

-   -   N- and O-dealkylation    -   Oxidative deamination    -   N-oxidation    -   Epoxidation

Reductive Activation

-   -   Azo reduction    -   Sulfoxide reduction    -   Disulfide reduction    -   Bioreductive alkylation    -   Nitro reduction.

Also to be mentioned as metabolic activations of prodrugs are nucleotideactivation, phosphorylation activation and decarboxylation activation.For additional information, see “The Organic Chemistry of Drug Designand Drug Action”, R B Silverman (particularly Chapter 8, pages 497 to546), incorporated herein by reference.

The use of protecting groups is fully described in ‘Protective Groups inOrganic Chemistry’, edited by J W F McOmie, Plenum Press (1973), and‘Protective Groups in Organic Synthesis’, 2nd edition, T W Greene & P GM Wutz, Wiley-Interscience (1991).

Thus, it will be appreciated by those skilled in the art that, althoughprotected derivatives of compounds of the disclosure may not possesspharmacological activity as such, they may be administered, for exampleparenterally or orally, and thereafter metabolised in the body to formcompounds of the invention which are pharmacologically active. Suchderivatives are therefore examples of “prodrugs”. All prodrugs of thedescribed compounds are included within the scope of the disclosure.

Some groups mentioned herein (especially those containing heteroatomsand conjugated bonds) may exist in tautomeric forms and all thesetautomers are included in the scope of the disclosure. More generally,many species may exist in equilibrium, as for example in the case oforganic acids and their counterpart anions; a reference herein to aspecies accordingly includes reference to all equilibrium forms thereof.

The compounds of the disclosure may also contain one or more asymmetriccarbon atoms and may therefore exhibit optical and/ordiastereoisomerism. All diastereoisomers may be separated usingconventional techniques, e.g. chromatography or fractionalcrystallisation. The various stereoisomers may be isolated by separationof a racemic or other mixture of the compounds using conventional, e.g.fractional crystallisation or HPLC, techniques. Alternatively thedesired optical isomers may be made by reaction of the appropriateoptically active starting materials under conditions which will notcause racemisation or epimerisation, or by derivatisation, for examplewith a homochiral acid followed by separation of the diastereomericderivatives by conventional means (e.g. HPLC, chromatography oversilica). All stereoisomers are included within the scope of thedisclosure. Where a single enantiomer or diasteromer is disclosed, thedisclosure also covers the other enantiomers or diastereomers, and alsoracemates; in this regard, particular reference is made to the specificcompounds listed herein.

Geometric isomers may also exist in the compounds of the presentdisclosure. The present disclosure contemplates the various geometricisomers and mixtures thereof resulting from the arrangement ofsubstituents around a carbon-carbon double bond and designates suchisomers as of the Z or E configuration, wherein the term “Z” representssubstituents on the same side of the carbon-carbon double bond and theterm “E” represents substituents on opposite sides of the carbon-carbondouble bond.

The disclosure therefore includes all variant forms of the definedcompounds, for example any tautomer or any pharmaceutically acceptablesalt, ester, acid or other variant of the defined compounds and theirtautomers as well as substances which, upon administration, are capableof providing directly or indirectly a compound as defined above orproviding a species which is capable of existing in equilibrium withsuch a compound.

Synthesis

The compounds may be synthesised as described in the patentspecifications referenced above, e.g. WO 04/103306 and US 2005/0014728.

Administration & Pharmaceutical Formulations

The compounds of the invention will normally be administered orally,intravenously, subcutaneously, buccally, rectally, dermally, nasally,tracheally, bronchially, by any other parenteral route, as an oral ornasal spray or via inhalation, The compounds may be administered in theform of pharmaceutical preparations comprising prodrug or activecompound either as a free compound or, for example, a pharmaceuticallyacceptable non-toxic organic or inorganic acid or base addition salt, ina pharmaceutically acceptable dosage form. Depending upon the disorderand patient to be treated and the route of administration, thecompositions may be administered at varying doses.

Typically, therefore, the pharmaceutical compounds of the invention maybe administered orally or parenterally (“parenterally” as used herein,refers to modes of administration which include intravenous,intramuscular, intraperitoneal, intrasternal, subcutaneous andintraarticular injection and infusion) to a host. In the case of largeranimals, such as humans, the compounds may be administered alone as analternative to administration as compositions in combination withpharmaceutically acceptable diluents, excipients or carriers.

Actual dosage levels of active ingredients in the pharmaceuticalcompositions of this invention may be varied so as to obtain an amountof the active compound(s) that is effective to achieve the desiredtherapeutic response for a particular patient, compositions, and mode ofadministration. The selected dosage level will depend upon the activityof the particular compound, the route of administration, the severity ofthe condition being treated and the condition and prior medical historyof the patient being treated. However, it is within the skill of the artto start doses of the compound at levels lower than required to achievethe desired therapeutic effect and to gradually increase the dosageuntil the desired effect is achieved.

In the treatment, prevention, control, amelioration, or alleviation of asymptom of a peripheral neuropathy, an appropriate dosage level willgenerally be about 0.01 to 500 mg per kg patient body weight per daywhich can be administered in single or multiple doses. The dosage levelmay be about 0.1 to about 250 mg/kg per day; e.g. about 0.5 to about 100mg/kg per day. A suitable dosage level may be about 0.01 to 250 mg/kgper day, about 0.05 to 100 mg/kg per day, or about 0.1 to 50 mg/kg perday. Within this range the dosage may be 0.05 to 0.5, 0.5 to 5 or 5 to50 mg/kg per day. For oral administration, the compositions may beprovided in the form of tablets containing 1.0 to 1000 milligrams of theactive ingredient, particularly 1.0, 5.0, 10.0, 15.0, 20.0, 25.0, 50.0,75.0, 100.0, 150.0, 200.0, 250.0, 300.0, 400.0, 500.0, 600.0, 750.0,800.0, 900.0 or 1000.0 milligrams of the active ingredient. Thecompounds may be administered on a regimen of 1 to 4 times per day,preferably once or twice per day. The dosage regimen may be adjusted toprovide the optimal therapeutic response.

According to a further aspect of the invention there is thus provided apharmaceutical composition including a compound of the disclosure, inadmixture with a pharmaceutically acceptable adjuvant, diluent orcarrier.

Pharmaceutical compositions of this invention for parenteral injectionsuitably comprise pharmaceutically acceptable sterile aqueous ornonaqueous solutions, dispersions, suspensions or emulsions as well assterile powders for reconstitution into sterile injectable solutions ordispersions just prior to use. Examples of suitable aqueous andnonaqueous carriers, diluents, solvents or vehicles include water,ethanol, polyols (such as glycerol, propylene glycol, polyethyleneglycol and the like), and suitable mixtures thereof, vegetable oils(such as olive oil) and injectable organic esters such as ethyl oleate.Proper fluidity can be maintained, for example, by the use of coatingmaterials such as lecithin, by the maintenance of the required particlesize in the case of dispersions and by the use of surfactants.

These compositions may also contain adjuvants such as preservative,wetting agents, emulsifying agents and dispersing agents. Prevention ofthe action of microorganisms may be ensured by the inclusion of variousantibacterial and antifungal agents, for example, paraben, chlorobutanolor phenol sorbic acid. It may also be desirable to include isotonicagents such as sugars or sodium chloride, for example. Prolongedabsorption of the injectable pharmaceutical form may be brought about bythe inclusion of agents (for example aluminum monostearate and gelatin)which delay absorption.

In some cases, in order to prolong the effect of the drug, it isdesirable to slow the absorption of the drug from subcutaneous orintramuscular injection. This may be accomplished by the use of a liquidsuspension of crystalline or amorphous material with poor watersolubility. The rate of absorption of the drug then depends upon itsrate of dissolution which, in turn, may depend upon crystal size andcrystalline form. Alternatively, delayed absorption of a parenterallyadministered drug form is accomplished by dissolving or suspending thedrug in an oil vehicle.

Injectable depot forms are suitably made by forming microencapsulematrices of the drug in biodegradable polymers, for examplepolylactide-polyglycolide. Depending upon the ratio of drug to polymerand the nature of the particular polymer employed, the rate of drugrelease can be controlled. Examples of other biodegradable polymersinclude poly(orthoesters) and poly(anhydrides). Depot injectableformulations may also prepared by entrapping the drug in liposomes ormicroemulsions which are compatible with body tissues. The injectableformulations can be sterilized, for example, by filtration through abacterial-retaining filter or by incorporating sterilizing agents in theform of sterile solid compositions which can be dissolved or dispersedin sterile water or other sterile injectable media just prior to use.

Solid dosage forms for oral administration include capsules, tablets,pills, powders and granules. In such solid dosage forms, the activecompound is typically mixed with at least one inert, pharmaceuticallyacceptable excipient or carrier such as sodium citrate or dicalciumphosphate and/or one or more: a) fillers or extenders such as starches,lactose, sucrose, glucose, mannitol and silicic acid; b) binders such ascarboxymethylcellulose, alginates, gelatin, polyvinylpyrrolidone,sucrose and acacia; c) humectants such as glycerol; d) disintegratingagents such as agar-agar, calcium carbonate, potato or tapioca starch,alginic acid, certain silicates and sodium carbonate; e) solutionretarding agents such as paraffin; f) absorption accelerators such asquaternary ammonium compounds; g) wetting agents such as cetyl alcoholand glycerol monostearate; h) absorbents such as kaolin and bentoniteclay and i) lubricants such as talc, calcium stearate, magnesiumstearate, solid polyethylene glycols, sodium lauryl sulfate and mixturesthereof. In the case of capsules, tablets and pills, the dosage form mayalso comprise buffering agents. Solid compositions of a similar type mayalso be employed as fillers in soft and hard-filled gelatin capsulesusing such excipients as lactose or milk sugar as well as high molecularweight polyethylene glycol, for example.

Suitably, oral formulations contain a dissolution aid. The dissolutionaid is not limited as to its identity so long as it is pharmaceuticallyacceptable. Examples include nonionic surface active agents, such assucrose fatty acid esters, glycerol fatty acid esters, sorbitan fattyacid esters (e.g. sorbitan trioleate), polyethylene glycol,polyoxyethylene hydrogenated castor oil, polyoxyethylene sorbitan fattyacid esters, polyoxyethylene alkyl ethers, methoxypolyoxyethylene alkylethers, polyoxyethylene alkylphenyl ethers, polyethylene glycol fattyacid esters, polyoxyethylene alkylamines, polyoxyethylene alkylthioethers, polyoxyethylene polyoxypropylene copolymers, polyoxyethyleneglycerol fatty acid esters, pentaerythritol fatty acid esters, propyleneglycol monofatty acid esters, polyoxyethylene propylene glycol monofattyacid esters, polyoxyethylene sorbitol fatty acid esters, fatty acidalkylolamides, and alkylamine oxides; bile acid and salts thereof (e.g.chenodeoxycholic acid, cholic acid, deoxycholic acid, dehydrocholic acidand salts thereof, and glycine or taurine conjugate thereof); ionicsurface active agents, such as sodium laurylsulfate, fatty acid soaps,alkylsulfonates, alkylphosphates, ether phosphates, fatty acid salts ofbasic amino acids; triethanolamine soap, and alkyl quaternary ammoniumsalts; and amphoteric surface active agents, such as betaines andaminocarboxylic acid salts.

The solid dosage forms of tablets, dragees, capsules, pills, andgranules can be prepared with coatings and shells such as entericcoatings and other coatings well known in the pharmaceutical formulatingart. They may optionally contain opacifying agents and may also be of acomposition such that they release the active ingredient(s) only, orpreferentially, in a certain part of the intestinal tract, and/or indelayed fashion. Examples of embedding compositions include polymericsubstances and waxes.

The active compounds may also be in micro-encapsulated form, ifappropriate, with one or more of the above-mentioned excipients.

The active compounds may be in finely divided form, for example it maybe micronised.

Liquid dosage forms for oral administration include pharmaceuticallyacceptable emulsions, solutions, suspensions, syrups and elixirs. Inaddition to the active compounds, the liquid dosage forms may containinert diluents commonly used in the art such as water or other solvents,solubilizing agents and emulsifiers such as ethyl alcohol, isopropylalcohol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzylbenzoate, propylene glycol, 1,3-butylene glycol, dimethyl formamide,oils (in particular, cottonseed, groundnut, corn, germ, olive, castor,and sesame oils), glycerol, tetrahydrofurfuryl alcohol, polyethyleneglycols and fatty acid esters of sorbitan and mixtures thereof. Besidesinert diluents, the oral compositions may also include adjuvants such aswetting agents, emulsifying and suspending agents, sweetening, flavoringand perfuming agents. Suspensions, in addition to the active compounds,may contain suspending agents such as ethoxylated isostearyl alcohols,polyoxyethylene sorbitol and sorbitan esters, microcrystallinecellulose, aluminum metahydroxide, bentonite, agar-agar, and tragacanthand mixtures thereof.

Compositions for rectal or vaginal administration are preferablysuppositories which can be prepared by mixing the compounds of thisinvention with suitable non-irritating excipients or carriers such ascocoa butter, polyethylene glycol or a suppository wax which are solidat room temperature but liquid at body temperature and therefore melt inthe rectum or vaginal cavity and release the active compound.

Compounds of the present invention can also be administered in the formof liposomes. As is known in the art, liposomes are generally derivedfrom phospholipids or other lipid substances. Liposomes are formed bymono- or multi-lamellar hydrated liquid crystals which are dispersed inan aqueous medium. Any non-toxic, physiologically acceptable andmetabolisable lipid capable of forming liposomes can be used. Thepresent compositions in liposome form can contain, in addition to acompound of the present invention, stabilisers, preservatives,excipients and the like. The preferred lipids are the phospholipids andthe phosphatidyl cholines (lecithins), both natural and synthetic.Methods to form liposomes are known in the art, for example, Prescott,Ed., Methods in Cell Biology, Volume XIV, Academic Press, New York, N.Y.(1976), p 33 et seq.

Advantageously, the compounds of the invention may be orally active,have rapid onset of activity and low toxicity.

The compounds of the invention may have the advantage that they are moreefficacious, less toxic, longer acting, have a broader range ofactivity, more potent, produce fewer side effects, more easily absorbedthan, or have other useful pharmacological properties over, compoundsknown in the prior art.

Combination Therapies

Compounds of the invention may be administered in combination with oneor more additional therapeutic agents. Accordingly, the inventionprovides a pharmaceutical composition comprising an additional agent.The invention also provides a product comprising a compound of theinvention and an agent; as a combined preparation for simultaneous,separate or sequential use in therapy.

In particular, a composition or product of the invention may furthercomprise a therapeutic agent selected from, for example, a compound ofthe disclosure may be administered in combination with an agent usefulfor treating a peripheral neuropathy, for example a demyelinatingperipheral neuropathy; as examples of such second agents may bementioned an immunosuppresant (e.g., cyclosporin A, cyclosporin G,FK-506, ABT-281, ASM981, rapamycin, 40-O-(2-hydroxy)ethyl-rapamycin,corticosteroids, cyclophosphamide, azathioprine, methotrexate,leflunomide, mizoribine, mycophenolate mofetil, or 15-deoxyspergualine),a steroid (e.g., prednisone or hydrocortisone), an immunoglobulin, ortype 1 interferon. The compound of the disclosure and the second agentcan be administered simultaneously or consecutively. Where the compoundof the disclosure and the second agent are administered simultaneously,they may be formulated into a single composition or in separatecompositions.

Use

Compounds of the invention may be useful in the therapy of a variety ofperipheral neurapathies, particularly acute or chronic demyelinatingneuropathies. The compounds of the disclosure therefore may be useful inthe therapy of one or more of Guillain-Barré syndrome (GBS), chronicinflammatory demyelinating polyradiculoneuropathy (CIDP), multifocalmotor neuropathy with conduction block (MMN), and paraproteinaemicdemyelinating peripheral neuropathy (PDN). In particular, the neuropathyis CIDP. The effectiveness of the compounds may vary between patients.

The term “therapy” includes treatment to alleviate one or more symptomsof a peripheral neurapathy or to delay progression of such a diseasee.g. by preventing or slowing demyelination e.g. peripheraldemyelination; it also includes treatment to cure such a disease, to puta subject into a functional state and/or maintain a subject in afunctional state, or to prolong time to relapse.

The therapeutic use of the compound may include prophylactic use toprevent, control or reduce the severity of a peripheral neurapathy whichthe subject is at risk of suffering, as well as treatment to control orreduce the severity of existing disease. The compound may beadministered before the onset of symptoms; it may be administered afterthe onset of symptoms. It may be administered to a subject at risk ofsuffering a a peripheral neurapathy.

The treatments for which the compounds may be used may thereforeimprove, maintain or delay the deterioration of the medical conditionand/or comfort of a patient having, suspected of having, or at risk ofhaving, a peripheral neurapathy.

EXAMPLE

The following Examples illustrate the invention.

Example 1 Synthesis of Compound A1-{4-[1-(4-Cyclohexyl-3-trifluoromethyl-benzyloxyimino)-ethyl]-2-ethyl-benzyl}-azetidine-3-carboxylicacid (compound A)

To a suspension of MnO₂ (10 eq) in dioxane is added1-(3-ethyl-4-hydroxymethyl-phenyl)-ethanoneO-(4-cyclohexyl-3-trifluoromethyl-benzyl)-oxime (1 eq). The resultingmixture is refluxed for 10 minutes. After filtration and concentration,the residue is dissolved in MeOH and treated with azetidine-3-carboxylicacid (2 eq) and Et3N (1.5 eq). The resulting mixture is heated at 50° C.for 30 minutes. After cooling to room temperature, NaBH₃CN (3 eq) isadded in portions. Purification by preparative LCMS results in1-{4-[1-(4-cyclohexyl-3-trifluoromethyl-benzyloxyimino)-ethyl]-2-ethyl-benzyl}-azetidine-3-carboxylicacid; ¹H NMR (400 MHz, CD₃OD) δ 1.24 (t, 3H), 1.30-1.60 (m, 5H),1.74-1.92 (m, 5H), 2.28 (s, 3H), 2.79 (q, 2H), 2.92 (m, 1H), 3.68 (m,1H), 4.32 (m, 4H), 4.51 (s, 2H) 5.22 (s, 2H), 7.38 (d, 1H), 7.50-7.68(m, 5H). MS: (ES⁺) : 517.3 (M+1)⁺.

Example 2 Suppressive Effect of Compound A on Experimental AutoimmuneNeuritis

Male Lewis rats (8-10 weeks, 180-200 g, Elevage-Janvier, France) werehoused under a 12 h light-12 h dark cycle and with free access to foodand water. All animal procedures were in accordance with a protocolapproved by the local Administration District Official Committee. Allefforts were made to minimize the number of animals and their suffering.

EAN Induction

For EAN induction, rats were immunized by subcutaneous injection intoboth hind footpads with 100 μL of an inoculum containing 100 μg ofsynthetic neuritogenic P2 57-81 peptide (GeneScript Corporation, ScotchPlains, N.J., USA). The peptide was dissolved in phosphate bufferedsaline (PBS) (2 mg/mL) and then emulsified with an equal volume ofcomplete Freund's adjuvant (CFA) containing 2 mg/mL mycobacteriumtuberculosis to get a final concentration of 1 mg/mL.

EAN clinical scores were evaluated every day as follows: 0=normal,1=reduced tonus of tail, 2=limp tail, impaired righting, 3=absentrighting, 4=gait ataxia, 5=mild paresis of the hind limbs, 6=moderateparaparesis, 7=severe paraparesis or paraplegia of the hind limbs,8=tetraparesis, 9=moribund, and 10=death (Zhang et al., 2009A).

Compound A Treatment

Compound A was separately tested at two concentrations of suspension (3and 10 mg/kg, suspended in 1% carboxymethylcellulose (CMC, Blanose,Hercules-Aqualon, Düsseldorf, Germany)). The compound A suspensions wereintragastrically administrated immediately after induction and then oncedaily until Day 22 (5 rats per group). For control EAN rats, the samevolume of 1% CMC in water was given.

Immunohistochemistry

To evaluate inflammatory cell infiltration and pathological changes inthe PNS, five compound A-treated rats (at both concentrations) and fivecontrol EAN rats from Day 16 were sacrified. Rats were deeplyanaesthetized with ether and perfused intracardially with 4° C., 4%paraformaldehyde in PBS. Left and right sciatic nerves were quicklyremoved and post-fixed in 4% formaldehyde overnight at 4° C. Sciaticnerves were cut into two equally long segments, embedded in paraffin,serially sectioned (3 μm) and mounted on silan-covered slides.

After dewaxing, cross-sections of sciatic nerves were boiled (in a 600 Wmicrowave oven) for 15 min in citrate buffer (2.1 g sodium citrate/L, pH6). Endogenous peroxidase was inhibited with 1% H₂O₂ in methanol for 15min. Sections were incubated with 10% normal pig serum (Biochrom,Berlin, Germany) to block non-specific binding of immunoglobulins andthen with the following monoclonal antibodies: W3/13 (1:50; Serotec,Oxford, UK) for T lymphocytes, OX22 (1:200; Serotec, Oxford, UK) for Bcells, ED1 for activated macrophages (1:100; Serotec, Oxford, UK).Antibody binding to tissue sections was visualized with biotinylated IgGF(ab)2 secondary antibody fragments (rabbit anti-mouse or rabbitanti-goat; 1:400; DAKO, Hamburg, Germany). Subsequently, sections wereincubated with a Streptavidin-Avidin-Biotin complex (DAKO, Hamburg,Germany), followed by development with diaminobenzidine (DAB) substrate(Fluka, Neu-Ulm, Germany). Finally, sections were counterstained withMaier's Hemalum.

To evaluate immunostaining data, the percentages of areas ofimmunoreactivity (IR) to areas of sciatic nerve cross-sections werecalculated. Images of sciatic nerve cross-sections were captured under50× magnification using Nikon Coolscope (Nikon, Düsseldorf, Germany)with fixed parameters. Images were analyzed using MetaMorph Offline 7.1(Molecular Devices, Toronto, Canada). Areas of IR were selected bycolour threshold segmentation and all parameters were fixed for allimages. Areas of sciatic nerve cross-sections were manually selected.For each EAN rat, four cross-sections from root and middle levels ofboth sides were analyzed. Results were given as arithmetic means ofpercentages of areas of IR to areas of sciatic nerve cross-sections andstandard errors of means (SEM).

The routine Luxol Fast Blue (LFB) staining was applied to show myelin.Histological changes between Compound A and control EAN rats werecompared by an established semi-quantitative method. Briefly, fourcross-sections from root and middle level of both sides of EAN rats wereanalyzed. All perivascular areas present in cross-sections wereevaluated by two observers unaware of the treatment, and the degree ofpathological alteration was graded semiquantitatively on the followingscale: 0=normal perivascular area; 1=mild cellular infiltrate adjacentto the vessel; 2=cellular infiltration plus demyelination in immediateproximity to the vessel; and 3=cellular infiltration and demyelinationthroughout the section. Results were given as mean histological score(Hartung et al., 1988).

Evaluation and Statistical Analysis

The unpaired t-test was performed to compare difference between CompoundA and control EAN rats (Graph Pad Prism 4.0 for windows). For allstatistical analyses, significance levels were set at p<0.05.

Results

Suppressive Treatment of EAN by Compound A

EAN was induced by subcutaneous injection of neuritogenic synthetic P2peptide. For suppressive treatment, 1% CMC in water (the control group)or compound A were orally administrated immediately after immunizationand then once daily until Day 22. The first neurologic signs (reducedtail tonus) of control EAN rats were observed at Day 9 (mean clinicalscore: 0.20±0.13). The neurologic severity of EAN increased fast in thecontrol group with a maximal score at Day 13 (mean neurologic score:4.80±0.51). Thereafter, the severity of EAN slowly decreased and ratsfully recovered by Day 22 (mean clinical scores: 0±0). In compoundA-treated EAN rats, greatly reduced neurological signs were seen at Day14, with maximal scores at Day 15 and full recovery of rats was seen byDay 19. Therefore, compound A treatment almost prevented the developmentof clinical signs of EAN, dramatically delayed its onset, decreasedneurologic severity and shortened duration of EAN very effectivelyrelative to the water/cmc vehicle (FIGS. 1A and 1B).

A further feature of EAN is progressive weight loss after onset ofdisease. In control and Compound A-treated EAN rats, a slow andcontinuous weight gain was observed until onset of EAN (Day 9).Thereafter, control EAN rats showed significant weight loss during theperiod of neurologic disease from Day 10 to 18 post immunization,followed by weight gain during the recovery period (FIG. 2A). Incontrast, a reduced level of weight loss was observed in the lowercompound A suspension from Day 11 to 16 in EAN rats treated by compoundA at the peak of disease onset, again indicating a much less severecourse. This effect was more pronounced in the higher dosage suspension,with a small weight loss between days 11 and 12, followed by weight gain(FIG. 2B).

Effects of Suppressive Compound A Treatment on Histopathological Changesin EAN Sciatic Nerves

Infiltration of different types of inflammatory cells in sciatic nervesof control or Compound A-treated EAN rats at Day 16 (n=5) was analyzedby immunohistochemistry. Infiltration of T cells (W3/13⁺), B cells(OX22⁺) and macrophages (ED1⁺) was seen in sciatic nerves of control EANrats. The predominant infiltrating cells were macrophages, whose areasof IR occupied about 2% of the total areas of sciatic nerve oncross-sections. These results are shown in Table 1 below.

TABLE 1 Area of immuno- Area of immuno- Area of immuno- reactivity/areareactivity/area reactivity/area of sciatic nerves of sciatic nerves ofsciatic nerves Test (%) for Macro- (%) for T cells (%) for B cellscompound phages (ED1+) (W3/13+) (OX22+) Water vehicle 2.1 0.6 0.25 CMCvehicle 2.2 0.56 0.91 Compound A 0.20 0.08 0.025 (3 mg/kg) Compound A0.11 0.04 0.021 (10 mg/kg)

In sciatic nerves of EAN rats, compound A significantly suppressedinfiltration of T cell, B cells and macrophages.

In sciatic nerves, the mean histological scores measured by LFB stainingwere markedly lower in Compound A-treated EAN rats. These results areshown in Table 2 below.

TABLE 2 Test composition Mean Histological Score Water vehicle 1.78 CMCvehicle 1.75 Compound A (3 mg/kg) 0.51 Compound A (10 mg/kg) 0.25

These results demonstrate that suppressive treatment with Compound Aalmost prevented EAN and inhibited paraparesis through substantialreduction of infiltration of lymphocytes and macrophages into theperipheral nerves along with decreased local demyelination.

1. A compound of formula A1 or A2 for use in the treatment of ademyelinating peripheral neuropathy:

wherein A is COOR₅, OPO(OR₅)₂, PO(OR₅)₂, SO₂OR₅, POR₅OR₅ or1H-tetrazol-5-yl, R₅ being H or an ester-forming group, optionallyC₁₋₆alkyl; W is a bond, C₁₋₃alkylene or C₂₋₃alkenylene; Y is C₆₋₁₀arylor C₂₋₉heteroaryl eg C₃₋₉heteroaryl, optionally substituted by 1 to 3radicals selected from halogen, OH, NO₂, C₁₋₆alkyl, C₁₋₆alkoxy;halo-substituted C₁₋₆alkyl and halo-substituted C₁₋₆alkoxy; Z is chosenfrom:

wherein the left and right asterisks of Z indicate the point ofattachment between —C(R₃)(R₄)— and A of Formula Ia or Ib, respectively;R₆ is chosen from hydrogen and C₁₋₆alkyl; and J₁ and J₂ areindependently methylene or a heteroatom chosen from S, O and NR₅;wherein R₅ is chosen from hydrogen and C₁₋₆alkyl; and any alkylene of Zcan be further substituted by one to three radicals chosen from halo,hydroxy, C₁₋₆alkyl; or R₆ can be attached to a carbon atom of Y to forma 5-7 member ring; R₁ is C₆₋₁₀aryl or C₂₋₉heteroaryl eg C₃₋₉heteroaryl,optionally substituted by C₁₋₆alkyl, C₆₋₁₀aryl, C₆₋₁₀arylC₁₋₄alkyl,C₃₋₉heteroaryl, C₃₋₉heteroarylC₁₋₄alkyl, C₃₋₈cycloalkyl,C₃₋₈cycloalkylC₁₋₄alkyl, C₃₋₈heterocycloalkyl orC₃₋₈heterocycloalkylC₁₋₄alkyl; wherein any aryl, heteroaryl, cycloalkylor heterocycloalkyl of R₁ may be substituted by 1 to 5 groups selectedfrom halogen, C₁₋₆alkyl, C₁₋₆alkoxy and halo substituted-C₁₋₆alkyl or-C₁₋₆alkoxy; R₂ is H, C₁₋₆alkyl, halo substituted C₁₋₆alkyl, C₂₋₆alkenylor C₂₋₆alkynyl; and each of R₃ and R₄, independently, is H, halogen, OH,C₁₋₆alkyl, C₁₋₆alkoxy or halo substituted C₁₋₆alkyl or C₁₋₆alkoxy; andthe N-oxide derivatives thereof or prodrugs thereof, or apharmacologically acceptable salt, solvate or hydrate thereof.
 2. Acompound of claim 1, wherein the neuropathy is Guillain-Barré syndrome.3. A compound of claim 1, wherein the neuropathy is chronic inflammatorydemyelinating polyradiculoneuropathy.
 4. A compound of claim 1, whereinthe neuropathy is multifocal motor neuropathy with conduction block. 5.A compound of claim 1, wherein the neuropathy is paraproteinaemicdemyelinating peripheral neuropathy.
 6. A compound of any precedingclaim, wherein A is COOR₅.
 7. A compound of claim 6, wherein A is COOH.8. A compound of any preceding claim, wherein W is ethylene.
 9. Acompound of any preceding claim, wherein Y is optionally substitutedphenyl or C₆heteroaryl.
 10. A compound of any of claims 1 to 8, whereinY is C₆₋₁₀aryl or C₃₋₉heteroaryl, substituted with a single C₁₋₆alkylsubstituent.
 11. A compound of claim 10, wherein Y is phenyl optionallysubstituted by ethyl.
 12. A compound of any preceding claim, wherein Zis selected from the heterocycles azetidine, pyrrolidine or piperidine,joined to the remainder of the molecule at the 1- and 3-positions; orpiperidine joined to the remainder of the molecule at the 1- and4-positions; optionally wherein the heterocycle is N-substituted(1-substituted) by moiety A and substituted at the 3 or, as the case maybe, 4-position by —C(R₃)(R₄)—.
 13. A compound of any preceding claim,wherein R₁ is optionally substituted phenyl or optionally substitutedC₆heteroaryl.
 14. A compound of any preceding claim, wherein R₁ has twosubstituents selected from optionally halo-substituted alkyl having 1,2, 3, 4, 5 or 6 carbon atoms, optionally halo-substituted phenyl andoptionally halo-substituted C₃₋₈cycloalkyl.
 15. A compound of claim 14wherein R₁ is phenyl or C₆heteroaryl.
 16. A compound of claim 15,wherein R₁ has one optionally halo-substituted alkyl group and oneoptionally halo-substituted cyclic moiety selected from phenyl andC₃₋₈cycloalkyl groups.
 17. A compound of any preceding claim, wherein R₂is methyl.
 18. A compound of any preceding claim, wherein R₃ and R₄ areeach independently H, halogen, methyl or halo-substituted methyl.
 19. Acompound of claim 18, wherein R₃ and R₄ are both H.
 20. A compound ofany of claims 1 to 5, wherein the compound is selected from:


21. A compound of any of claims 1 to 5, wherein the compound is1-{4-[1-(4-Cyclohexyl-3-trifluoromethyl-benzyloxyimino)-ethyl]-2-ethyl-benzyl}-azetidine-3-carboxylicacid:


22. A method of treating a subject having a demyelinating peripheralneuropathy comprising administering to the subject an effective amountof a compound having a structure defined in any of claims 1 and 6 to 21.23. A method of alleviating a symptom of, delaying the progression of,or prolonging time to relapse of a demyelinating peripheral neuropathycomprising administering to the subject an effective amount of acompound having a structure defined in any of claims 1 and 6 to
 21. 24.A method of improving or maintaining, or delaying the deterioration of,the status of a subject having a demyelinating peripheral neuropathycomprising administering to the subject an effective amount of acompound having a structure defined in any of claims 1 and 6 to
 21. 25.A method of claim 22, 23 or 24, wherein the neuropathy is Guillain-Barrésyndrome.
 26. A method of claim 22, 23 or 24, wherein the neuropathy ischronic inflammatory demyelinating polyradiculoneuropathy.
 27. A methodof claim 22, 23 or 24, wherein the neuropathy is multifocal motorneuropathy with conduction block.
 28. A method of claim 22, 23 or 24,wherein the neuropathy is paraproteinaemic demyelinating peripheralneuropathy.
 29. A pharmaceutical formulation comprising a compoundhaving a structure defined in any of claims 1 and 6 to 21 in combinationwith at least one further therapeutic agent useful for treating apatient having a demyelinating peripheral neuropathy.
 30. A formulationof claim 29, wherein the at least one further therapeutic agent isselected from an immunosuppresant (e.g., cyclosporin A, cyclosporin G,FK-506, ABT-281, ASM981, rapamycin, 40-O-(2-hydroxy)ethyl-rapamycin, acorticosteroid, cyclophosphamide, azathioprine, methotrexate,leflunomide, mizoribine, mycophenolate mofetil, or 15-deoxyspergualine),a steroid (e.g., prednisone or hydrocortisone), an immunoglobulin, ortype 1 interferon.
 31. A compound having a structure defined in any ofclaims 1 and 6 to 21 for simultaneous, separate or sequentialco-administration with at least one further agent as defined in claim 29or 30.